In dentistry powder jet devices are currently used for applying a fluid stream of abrasive particles, air and water to the tooth structure of a patient, for example for cleaning or pretreating the tooth surfaces.
Generally, a powder jet device may comprise a nozzle head through which the fluid stream can be delivered. Typically the fluid stream contains powder particles which are dispersed and entrained by an air stream guided through a powder containing chamber, and a liquid optionally added to the air/powder mixture, for example through a separate nozzle. In a device of that type used for cleaning tooth surfaces the powder material often comprises dental abrasive particles, and the liquid is normally water.
Examples of powder jet devices for use in the field of dentistry are described in U.S. Pat. No. 4,676,749 (Mabille) or U.S. Pat. No. 5,857,851 (Chavanne). The nozzle head of the device of U.S. Pat. No. 4,676,749 (Mabille) is screwed to the hand piece. The nozzle head of U.S. Pat. No. 5,857,851 (Chavanne) is locked to the hand piece by means of a single snap ring retention. Alternatively, a bayonet mechanism may be used.
Although known devices provide a variety of advantages there is still a desire for a device which is easy to use, which is relatively inexpensive but meets safety expectations of users and hygiene standards, for example as established in dentists' offices.